1. Field of the Invention
The present invention relates to a syringe with a liquid leak preventing mechanism, and specifically to a mechanism for preventing liquid leaking from syringe.
2. Description of Related Art
In a two-ingredient type pre-filled syringe charged with a predetermined medicine and a liquid such as its dissolution liquid, its dispersing liquid or other medicinal liquids in separated states, of the disposable type syringes previously filled with a medicine, so-called pre-filled syringes, conventionally as exemplified in FIG. 10, there has been known in Japanese Patent Publication No. 49-14465 a syringe having a construction such that an end sealing member 32 is inserted through a rear end opening into a cylindrical receptacle or barrel 31 provided at its leading end portion with a mounting portion for a needle. The barrel 31 has an intermediate sealing member 33 arranged therein so as to be slidable in a longitudinal or axial direction and to have a first chamber 34 on the leading end side and a second chamber 35 on the rear end side, divided therein to receive a medicine P and a dissolution liquid L within the respective chambers, and with its leading end portion closed by a cap 37.
This one type has such a construction that the first chamber 34, on the leading end side ahead of the intermediate slidable sealing member 33, has a bypass portion, usually an outwardly protruded bypass channel 36, arranged in the side wall of the barrel 31. At the time of use, the intermediate sealing member 33 is advanced together with the liquid L within the second chamber 35 by pushing the end sealing member 32 by means of a rod as shown in FIG. 11, and the liquid L within the second chamber 35 is made to flow into the first chamber 34 through the bypass channel 36 when the intermediate sealing member 33 reaches the channel 36. As shown in FIG. 12, subsequently thereto, the intermediate sealing member 33 is pushed by the leading end of the end sealing member 32 to perform the dissolution, the dispersion or the mixing within the first chamber 34, and then the liquid is pushed out of the leading end.
Since the end sealing member passes the bypass portion, the liquid remaining in the bypass portion leaks behind the end sealing member. Therefore, a mechanism for preventing a liquid leak outside of the syringe, by arranging a partition plate behind the end sealing member was proposed in Japanese Patent Publication (unexamined) No. 62-14863.
In this method, however, a low-viscosity medicinal liquid, a small surface-tension liquid and the like happen to pass through a gap between the partition plate provided in the plunger rod and the barrel inner wall, and it is apprehended that the medicinal liquid remaining in the partition plate flows out when the plunger rod is removed from the syringe for fractional scrapping.
Therefore, it is an object of the invention to provide a syringe with a liquid leak preventing mechanism which is capable of preventing a medicinal liquid from passing out through a gap between a receptacle or barrel inner wall and a partition plate and also from flowing out when a plunger rod is dismounted from the syringe for fractional scrapping.